x1,y1,x2,y2=map(float,input().split())
p=((x1-x2)**2+(y1-y2)**2)**0.5
print(f'{p:.8f}') x1,y1,x2,y2=map(float,input().split()) x1 map(float,input().split()) map float input().split() ().split () input split y1 x2 y2 p=((x1-x2)**2+(y1-y2)**2)**0.5 p ((x1-x2)**2+(y1-y2)**2)**0.5 (x1-x2)**2+(y1-y2)**2 (x1-x2)**2 x1-x2 x1 x2 2 (y1-y2)**2 y1-y2 y1 y2 2 0.5 print(f'{p:.8f}') print f'{p:.8f}' x1,y1,x2,y2=map(float,input().split()) map(float,input().split()) x1 y2=map(float,input().split()) map(float,input().split()) y2 x2,y2=map(float,input().split()) map(float,input().split()) x2 y1,x2,y2=map(float,input().split()) map(float,input().split()) y1 p=((x1-x2)**2+(y1-y2)**2)**0.5 ((x1-x2)**2+(y1-y2)**2)**0.5 p
x1,y1,x2,y2=map(float,input().split())
p=((x1-x2)**2+(y1-y2)**2)**0.5
print(f'{p:.8f}')
